Dear student.
Insulin is secreted to regulate the blood glucose level.
In our body, hormone insulin has been secreted by special cells called islets of langerhans found in the pancreas. The function of insulin is to regulate the normal blood glucose level. Insulin increases the permeability of cell membrane and accelerate the passage of glucose into the cells from the bloodstream. When these cells do not secrete enough insulin, the level of glucose rises in the blood causing diabetes. Sometimes, the level of sugar is so high in the blood that sugar is passed out along with urine and sugar can be detected in urine test.
Regards.